Continuous variable valve lift apparatus

ABSTRACT

A continuous variable valve lift apparatus may include a camshaft, a first cam disposed on the camshaft, an actuating shaft parallel to the cam shaft, an actuating lever connected to the actuating shaft, a swing arm rotatably coupled to the actuating lever and an engine, a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit and a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft for pivoting center of the swing arm to move.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority of Korean Patent Application Number 10-2010-0120915 filed in the Korean Intellectual Property Office on Nov. 30, 2010, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a valve lift apparatus. More particularly, the present invention relates to a continuous variable valve lift apparatus which may adjust valve lift.

2. Description of Related Art

An internal combustion engine generates power by burning fuel in a combustion chamber in air media drawn into the chamber. Intake valves are operated by a cam shaft in order to intake the air, and the air is drawn into the combustion chamber while the intake valves are open. In addition, exhaust valves are operated by the cam shaft, and a combustion gas is exhausted from the combustion chamber while the exhaust valves are open.

An optimal operation of the intake valves and the exhaust valves depends on a rotation speed of the engine. That is, an optimal lift or optimal opening/closing timing of the valves depends on the rotation speed of the engine. In order to achieve such an optimal valve operation depending on the rotation speed of the engine, various researches, such as designing a plurality of cam and a variable valve lift (VVL) that can change valve lift according to engine speed, have been undertaken.

However, a conventional variable valve lift apparatus requires a lot of elements and manufacturing cost is high. And also, friction between each element is considerable and dynamic load is high and thus engine efficiency is deteriorated.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY OF INVENTION

Various aspects of the present invention have been made in an effort to provide a continuous variable valve lift apparatus having advantages of continuously varying valve lift with simple scheme and small total elements, and reducing manufacturing cost. As such, friction between each element may be reduced, dynamic load may be reduced, and reproducibility may be enhanced.

An exemplary continuous variable valve lift apparatus according to the present invention may include a camshaft, a first cam disposed on the camshaft, an actuating shaft parallel to the camshaft, an actuating lever connected to the actuating shaft, a swing arm rotatably coupled to the actuating lever and an engine, a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit and a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft to move the pivoting center of the swing arm.

A swing arm shaft may be disposed to the swing arm and the second cam may pivot around the swing arm shaft. A sliding portion may be formed on the actuating lever and the swing arm may be connected to the actuating lever via a control pin which is inserted into the sliding portion and slides along the sliding portion.

The sliding portion may be formed as an ellipse shape or other shapes such that one end of the sliding potion is closer to the actuating shaft than the other end.

A connecting pin may penetrate the actuating shaft and the actuating lever for connecting the actuating shaft and the actuating lever, and a snap ring may be connected to an end of the connecting pin for the connecting pin not to be separated therefrom.

The second cam may include a contact portion contacting the first cam, and a driving portion opening the valve unit. A contact portion roller may be disposed to the contact portion.

The control portion may include a worm wheel disposed to the actuating shaft, a worm gear engaged with the worm wheel and a control motor driving the worm gear.

Another exemplary continuous variable valve lift apparatus according to an exemplary embodiment of the present invention may include a cam shaft, a first cam disposed on the camshaft, an actuating shaft parallel to the camshaft, an actuating lever connected to the actuating shaft, a swing arm rotatably coupled to the actuating lever and an engine, a swing arm shaft disposed to the swing arm. a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit and a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft for pivoting center of the swing arm to move.

A sliding portion may be formed on the actuating lever and the swing arm may be connected to the actuating lever via a control pin which is inserted into the sliding portion and slides along the sliding portion.

The sliding portion may be formed as an ellipse shape or other shapes such that one end of the sliding potion is closer to the actuating shaft than the other end.

A connecting pin may penetrate the actuating shaft and the actuating lever for connecting the actuating shaft and the actuating lever, and a snap ring may be connected to an end of the connecting pin for the connecting pin not to be separated therefrom.

The second cam may include a contact portion contacting the first cam, and a driving portion opening the valve unit. A contact portion roller may be disposed to the contact portion.

The control portion may include a worm wheel disposed to the actuating shaft, a worm gear engaged with the worm wheel and a control motor driving the worm gear.

The continuous variable valve lift apparatus according to exemplary embodiments of the present invention may continuously vary valve lift with simple scheme and small total number of elements, and reducing manufacturing cost. As such, friction between each element may be reduced, dynamic load may be reduced, and reproducibility may be enhanced.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary continuous variable valve lift apparatus according to the present invention.

FIG. 2 is a partial exploded view of an exemplary continuous variable valve lift apparatus according to the present invention.

FIG. 3 is a perspective view of a second cam of exemplary continuous variable valve lift apparatuses according to the present invention.

FIGS. 4 and 5 are perspective views showing configurations of an exemplary continuous variable valve lift apparatus according to the present invention.

FIG. 6 is a cross-sectional view of an actuating lever of exemplary continuous variable valve lift apparatuses according to the present invention.

FIG. 7 is a perspective view of a snap ring of exemplary continuous variable valve lift apparatuses according to the present invention.

FIG. 8 is a drawing showing operations of an exemplary continuous variable valve lift apparatus according to the present invention.

FIG. 9 is a drawing showing driving portion of an exemplary continuous variable valve lift apparatus according to the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 1 to FIG. 5, exemplary continuous variable valve lift apparatuses according to the present invention may include a camshaft 10, a first cam 20 disposed on the camshaft 10, an actuating shaft 30 parallel to the cam shaft 10, an actuating lever 40 connected to the actuating shaft 30, a swing arm 50 rotatably coupled to the actuating lever 40 and an engine 90, a second cam 60 pivotally connected to the swing arm 50 and contacting the first cam 20 to open a valve unit 100 and a control portion 70 which is connected to the actuating shaft 30 and selectively rotates the actuating shaft 30 to move the pivoting center of the swing arm 50.

Referring to FIG. 1 and FIG. 5, the swing arm 50 is pivotally coupled to the engine 90 via a connecting portion 56 and the engine 90 includes a cylinder head, a valve train and so on. A swing arm shaft 52 is disposed to the swing arm 50 and the second cam 60 pivots around the swing arm shaft 52. That is, the swing arm shaft 52 is the pivoting center of the swing arm 50.

Referring to FIG. 2, a sliding portion 42 is formed on the actuating lever 40 and the swing arm 50 is connected to the actuating lever 40 via a control pin 54 which is inserted into the sliding portion 42 and slides along the sliding portion 42. The sliding portion 42 is formed as an ellipse shape or other shapes such that one end of the sliding potion 42 is closer to the actuating shaft 30 than the other end.

Referring to FIGS. 3-4, the second cam 60 includes a contact portion 62 contacting the first cam 20, and a driving portion 64 opening the valve unit 100. A contact portion roller 62 is disposed to the contact portion 62.

As shown in FIG. 1, the control portion 70 includes a worm wheel 72 disposed to the actuating shaft 30, a worm gear 74 engaged with the worm wheel 72 and a control motor 76 driving the worm gear 74.

Referring to FIG. 6 and FIG. 7, a connecting pin 80 penetrates the actuating shaft 30 and the actuating lever 40 for connecting the actuating shaft 30 and the actuating lever 40, and a snap ring 82 is connected to an end of the connecting pin 80 for the connecting pin 80 not to be separated therefrom.

Hereinafter, the operations of exemplary continuously variable valve lift apparatuses of the present invention will be described with the accompaning drawings FIGS. 1-9.

When low lift is required according to engine operation condition, an engine control unit (ECU) controls the control motor 76 so that the actuating shaft 30 rotates in the anticlockwise direction as shown in FIG. 8. Operations of the ECU, the control motor 76 and so on are obvious to a person skilled in the art of the present invention and thus detailed description will be omitted.

And then, the actuating lever 40 connected to the actuating shaft 30 also rotates anticlockwise direction, and the control pin 54 moves along the sliding portion 42. The sliding portion 42 is formed as an ellipse shape or other shapes for the swing arm 50 to rotate around the connecting portion 56. And thus, the swing arm 50 rotates to anticlockwise direction around the connecting portion 56 according to the rotation of the actuating lever 40.

Pivotally connected to the swing arm 50, the second cam 60 rotates along with the swing arm 50. As such, the relative contact position between the driving portion 64 and the valve unit roller 102 changes as in FIG. 3 and FIG. 9. That is, when engine operation condition is changed from a high lift mode to a low lift mode, the relative contact position between the driving portion 64 and the valve unit roller 102 moves to the left side as shown in FIG. 9 b). In the low lift mode, the relative contacting position of the driving portion 64 is at its relatively low position so that the valve lift is reduced accordingly.

When high valve lift is required, the actuating shaft 30 rotates to clockwise direction and also the swing arm 50 rotates to clockwise direction as shown in FIG. 8. And then, the relative contact position between the valve unit roller 102 and the driving portion 64 moves as shown in FIG. 9 a), and thus the valve lift is increased.

Although only operations of the high and low lift modes are described, the continuous variable valve lift of the present invention may realize continuous valve lift changes corresponding to the relative conatcting positions.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

1. A continuous variable valve lift apparatus for a vehicle engine comprising: a camshaft; a first cam disposed on the camshaft; an actuating shaft parallel to the camshaft; an actuating lever connected to the actuating shaft; a swing arm rotatably coupled to the actuating lever and pivotally mounted within a cylinder head of the engine; a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit; and a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft to move a pivoting center of the swing arm.
 2. The continuous variable valve lift apparatus of claim 1, wherein: a swing arm shaft is disposed to the swing arm; and the second cam pivots around the swing arm shaft.
 3. The continuous variable valve lift apparatus of claim 1, wherein: a sliding portion is formed on the actuating lever; and the swing arm is connected to the actuating lever via a control pin which is inserted into the sliding portion and slides along the sliding portion.
 4. The continuous variable valve lift apparatus of claim 3, wherein the sliding portion is formed in a shape such that one end of the sliding potion is closer to the actuating shaft than the other end thereof.
 5. The continuous variable valve lift apparatus of claim 4, wherein the sliding portion is formed as an ellipse shape.
 6. The continuous variable valve lift apparatus of claim 3, wherein: a connecting pin penetrates the actuating shaft and the actuating lever for connecting the actuating shaft and the actuating lever; and a snap ring is connected to an end of the connecting pin for the connecting pin not to be separated therefrom.
 7. The continuous variable valve lift apparatus of claim 1, wherein the second cam comprises: a contact portion contacting the first cam; and a driving portion opening the valve unit.
 8. The continuous variable valve lift apparatus of claim 7, wherein a contact portion roller is disposed to the contact portion.
 9. The continuous variable valve lift apparatus of claim 1, wherein the control portion comprises: a worm wheel disposed to the actuating shaft; a worm gear engaged with the worm wheel; and a control motor driving the worm gear.
 10. A continuous variable valve lift apparatus for a vehicle engine comprising: a cam shaft; a first cam disposed on the camshaft; an actuating shaft parallel to the cam shaft; an actuating lever connected to the actuating shaft; a swing arm rotatably coupled to the actuating lever and pivotally mounted within a cylinder head of the engine; a swing arm shaft disposed to the swing arm; a second cam pivotally connected to the swing arm and contacting the first cam to open a valve unit; and a control portion which is connected to the actuating shaft and selectively rotates the actuating shaft to move a pivoting center of the swing arm.
 11. The continuous variable valve lift apparatus of claim 10, wherein: a sliding portion is formed on the actuating lever; and the swing arm is connected to the actuating lever via a control pin which is inserted into the sliding portion and slides along the sliding portion.
 12. The continuous variable valve lift apparatus of claim 11, wherein the sliding portion is formed in a shape such that one end of the sliding potion is closer to the actuating shaft than the other end thereof.
 13. The continuous variable valve lift apparatus of claim 12, wherein the sliding portion is formed as an ellipse shape.
 14. The continuous variable valve lift apparatus of claim 10, wherein: a connecting pin penetrates the actuating shaft and the actuating lever for connecting the actuating shaft and the actuating lever; and a snap ring is connected to an end of the connecting pin for the connecting pin not to be separated therefrom.
 15. The continuous variable valve lift apparatus of claim 10, wherein the second cam comprises: a contact portion contacting the first cam; and a driving portion opening the valve unit.
 16. The continuous variable valve lift apparatus of claim 15, wherein a contact portion roller is disposed to the contact portion.
 17. The continuous variable valve lift apparatus of claim 10, wherein the control portion comprises: a worm wheel disposed to the actuating shaft; a worm gear engaged with the worm wheel; and a control motor driving the worm gear. 